Clinical utility analysis of the Hoxb8 mast cell activation test for the
diagnosis of peanut allergy
Abstract
Background: Peanut allergy is among the most severe and
common food allergies. The diagnosis has a significant impact on the
quality of life for patients and their families. An effective management
approach depends on accurate, safe, and easily implementable diagnostic
methods. We previously developed a cell-based assay using Hoxb8 mast
cells (Hoxb8 MCs) aimed at improving clinical allergy diagnosis. In this
study we assessed its diagnostic performance by measuring blinded sera
from a prospectively enrolled and pre-validated peanut allergy cohort.
Methods: Hoxb8 MCs were passively sensitized with sera
from peanut-allergic and peanut tolerant children and adolescents
(n=96). Degranulation of Hoxb8 MCs was quantified upon stimulation with
dose-titrated peanut extract by means of flow cytometry, using CD107a as
activation marker. The results from the Hoxb8 mast cell activation test
(Hoxb8 MAT) were compared to established diagnostic assays such as the
skin prick test (SPT), specific IgE (sIgE) levels, and the basophil
activation test (BAT). Additionally, serum samples from BAT
non-responders were assessed with the Hoxb8 MAT.
Results: Hoxb8 MAT displayed a robust dose-dependent
activation to peanut extract, with a cut-off value of ≤5.2% CD107a
positive cells. The diagnostic accuracy was highest at allergen
concentrations ≥100 ng/ml, with an area under the receiver operating
characteristic curve (AUROC) of 0.97, 93% sensitivity, and 96%
specificity, outperforming traditional SPT and sIgE tests. When compared
to BAT, Hoxb8 MAT exhibited comparable diagnostic efficacy. However,
sera from BAT non-responders were accurately classified into allergics
and non-allergics by the Hoxb8 MAT. Conclusions: The
Hoxb8 MAT demonstrated a very good diagnostic precision in patients
prospectively assessed for peanut allergy comparable to the fresh blood
based BAT. It also demonstrated its value for accurate classification of
BAT non-responders into allergic and non-allergic individuals. Further
investigations into its utility in the routine clinical setting are
warranted.